Providing location information for user equipment in a visited network

ABSTRACT

A method for establishing a media for communications in association with a location information service provided in association with a communication system is disclosed. In the method a user equipment is provided with information enabling the user equipment to communicate on a user plane connection with at least one location service entity when the user equipment is visiting a communication network other than a home network of the user equipment. This information may then be used for establishment of a user plane connection in the visited communication network between the user equipment and a location service entity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 10/787,972, filed on Feb.27, 2004. The subject matter of this earlier filed application is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to location information services provided inassociation with a communication system, and in particular tocommunication of information when providing information about a locationof a mobile user equipment visiting a network other than a home network.

2. Description of the Related Art

Various services can be provided for a user of a mobile user equipmentby means of a communication system. Recent development in the field ofmobile user equipment has lead to arrangements wherein information aboutthe location of a mobile user equipment is determined and utilized whenproviding services for the user equipment or other parties. Suchservices are sometimes called location sensitive services.

A mobile user equipment may comprise, for example, a mobile telephone, alaptop computer, a personal data assistant or any other mobile stationenabled for wireless communication with another station. An example of acommunication system providing mobility for users thereof is the publicland line mobile network (PLMN) or cellular network. Another example isa mobile communication system that is based, at least partially, on useof communication satellites. Wireless communications may also beprovided by means of other arrangements, such as by means of localwireless area networks.

The skilled person is aware of the basic principles of a wirelesscommunication system. A wireless communication system typically operatesin accordance with a given standard or specification which sets out whatthe various elements of the system are permitted to do and how thatshould be achieved. For example, the standard or specification maydefine if the user, or more precisely, user equipment or terminal isprovided with a circuit switched service or a packet switched service orboth. Communication protocols and/or parameters which shall be used forthe connection are also typically defined. For example, the manner howcommunication shall be implemented between the user equipment and theelements of the communication network is typically based on a predefinedcommunication protocol. In other words, a specific set of “rules” onwhich the communication can be based on needs to be defined to enablecommunication by means of the communication system.

A communication system needs to be able to provide various differentfunctions in order be able to operate. These functions can be divided indifferent categories. A category comprises functions that relate to theactual carrying of communications such as voice or multimedia or otherdata content in the system. Another category can be seen as being formedby control or management functions such as the control of variousservices and the actual communication. Signaling associated withdifferent functions is thus understood as being carried on differentplanes. For example, control messages are communicated on a controlplane and the actual communication is transported on a user plane. Thecommunication on the user plane is supported the signaling of thecontrol messages on the control plane. The predefined rules commonlydictate the appropriate plane that shall be used for communication.

Typically the communication systems provide the different planes bymeans of separate channels, e.g. by means of separated signaling andcommunication channels. Such arrangements are employed e.g. by signalingsystem 7 (SS7) core networks and Q.931/GSM/WCDMA subscriber access.Therefore the term signaling channel may be used when referring tocontrol plane communications. Similarly the term communication channelmay be used when referring to user plane communications.

The various functions of communication systems may have developed quiteindependently from each other. Different protocols may also be used indifferent communication systems. The standards and protocols define e.g.which plane shall be used for a certain purpose.

The mobile network apparatus and/or user equipment can be employed forprovision of information regarding the geographical location of the userequipment and thus the user thereof. A mobile user equipment and thusthe user thereof can be positioned by various different techniques. Forexample, substantially accurate geographical location information thatassociates with a user equipment can be obtained based on a satellitebased positioning system, for example the GPS (Global PositioningSystem) or Galileo. More accurate location information can be obtainedthrough a differential GPS or an assisted GPS (A-GPS). In an approachthe cells or similar geographically limited radio access entities andassociated controllers of the communication system are utilized inproduction of an estimate concerning the location of a mobile userequipment. To improve the accuracy of the location information thecommunication system may be provided with additional equipment, forexample specific location measurement units (LMUs), that provide moreaccurate data or additional data that may be used when locating of auser equipment.

It is also possible to conclude information about the geographicallocation of a user equipment when the user equipment is located outsidea home network thereof, i.e. when the user equipment is located in acoverage area of a visited or “foreign” network. The visited network maybe made capable of transmitting the location of the mobile userequipment back to the home network, e.g. to support services that arebased on location information or for the purposes of routing andcharging.

Location information may be used for various purposes, such as forlocation of a mobile telephone that has made an emergency call, forlocating vehicles or given mobile subscribers for commercial purposesand so on. In general, a client (for example a user or another entitywishing to receive location information regarding a user may) may send arequest for location information to the location service provisionentity. An appropriate location service entity will then process therequest, obtain the required data and generate an appropriate response.

Communication associated with location services may be signaled on thecontrol plane and/or user plane, the selection depending on theapplication.

Applications that use control plane for communication of at least a partof information for location determination commonly employ embeddedsignaling protocols. Communications that associate with locationinformation services may be communicated solely on the control plane.However, this may cause relatively high load on the control plane. Thismay be especially the case on the air interface between a mobile userequipment and a radio network servicing the mobile user equipment.

It has been proposed that a mobile user equipment could be located byusing user plane signaling for communication of at least a part oflocation service information. Some of user plane applications are a kindof overlay solutions wherein a data connection is established on a userplane between a relevant server and a mobile user equipment to transferon radio interface information that is needed in locationdeterminations. The user plane data connection may be especiallyestablished for communication of location information. In anotherapproach location information may be communicated on a user planeconnection established for other purposes. The user plane signaling maybe based on appropriate communication protocol, for example the InternetProtocol (IP) or data messages such as short message service messages.An example of the proposals presented in Open Mobile Alliance (OMA)wherein user plane is used is known by the work name ‘Secure User PlaneLocation’ (SUPL).

In practice a user plane location system requires that the mobile userequipment knows an address or other routing information for a user planelocation server so that the mobile user equipment can exchangeinformation with the server on the user plane. A user plane locationserver may also need to know the identity, such as the Mobile SubscriberIntegrated Services Digital Number (MSISDN) or other identifier, of themobile user equipment or other routing information in order to form auser plane connection to the mobile user equipment.

The proposal is believed to work satisfactorily when the user is inhis/hers home network. However, problems may arise when a user isroaming in other networks. A roaming mobile user equipment may not knowthe address or other identity information related to the local userplane enabled location service entity, for example a local SUPL server.If a user equipment knows only the address of the home network locationservice entity, a problem is that the home network location serviceentity may not be able to provide assistance data relevant and valid inthe roamed network. If a mobile station gets a location request from auser plane enabled location service entity while roaming, the userequipment may need to be able to trust that the location service entityis a legitimate entity allowed to request location information and tosend assistance data.

As a more detailed example of the possible problems, lets consider asituation where a user who is a subscriber to a Finnish cellular networkroams in a cellular network in the USA. The mobile user equipment of theuser is not aware of the IP address of the local server, for example alocal SUPL server, of the roamed network in the USA. The local servermay nevertheless need the location of the roaming user equipment, forexample in order to be able to provide the location of the roaming userequipment for emergency services. In the case of an emergency call thelocal server of the roamed network may try to request locationinformation from the mobile user equipment, but the mobile userequipment does not know whether it can trust the origin of the requestor not. Furthermore, if the mobile user equipment wants to getassistance data, it is possible in certain applications that the userequipment may only know the user plane address of a location serviceserver in the home network in Finland. The home network server, however,may not have all assistance data that is needed for location in the USA.

SUMMARY OF THE INVENTION

Embodiments of the present invention aim to address one or several ofthe above problems.

According to one embodiment of the present invention, a method forestablishing a media for communications in association with a locationinformation service provided in association with a communication systemcomprises the step of providing a user equipment with informationenabling the user equipment to communicate on a user plane connectionwith at least one location service entity when the user equipment isvisiting a communication network other than a home network of the userequipment. This information may then be used for establishment of a userplane connection in the visited communication network between the userequipment and a location service entity.

According to another embodiment there is provided a location servicearrangement for providing location information regarding a userequipment in communication with a communication system. Thecommunication system comprises a plurality of networks, one of thenetworks being the home network of the user equipment and at least oneother network being a network the user equipment is allowed to visit.The location service arrangement comprises a home location serviceentity of the user equipment and at least one further location serviceentity associated with at least one of said other networks. Thearrangement is such that the user equipment is configured to useinformation regarding at least one user plane address of at least onelocation service entity and to communicate location service informationon a user plane when visiting a network other than the home network.

According to yet another embodiment there is provided a user equipmentconfigured for communication with at least two networks, one of thenetworks being the home network of the user equipment and at least oneother network being a visited network. The user equipment is configuredto use information regarding at least one user plane address of at leastone location service entity and to communicate location serviceinformation on a user plane when visiting a network other than the homenetwork.

The embodiments may enable employment of user plane communication ofinformation associated with location services for a roaming userequipment in a visited network.

BRIEF DESCRIPTION OF DRAWINGS

For better understanding of the present invention, reference will now bemade by way of example to the accompanying drawings in which:

FIG. 1 shows a communication system wherein the present invention may beembodied;

FIG. 2 is a flowchart illustrating the operation of one specificembodiment;

FIGS. 3 to 6 show examples for providing a user plane connection betweena roaming user equipment and a network entity of a visited network; and

FIG. 7 shows a further embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is first made to FIG. 1 which is a simplified presentation ofa communication system in which the present invention may be embodied.It shall be appreciated that although this specification makesreferences to various elements associated with specific types of radioaccess networks and communication systems, these are shown and describedonly to facilitate the understanding of the invention. Similarfunctionalities may be provided by a number of alternative arrangements.

More particularly, FIG. 1 shows two cellular networks 2 and 3 providingmobility for a mobile user equipment 1. Network 2 is a home network ofthe user equipment 1, i.e. a network the user equipment 1 subscribes to.Network 3 is a visited network, i.e. a network the user equipment 1 hasroamed into. An interface 4 is provided for connecting the networks.

Each of the networks 2 and 3 is provided with an appropriate number ofradio access networks i.e. cells. The mobile user equipment 1 maycommunicate on a wireless interface with a base station 5 of a servingaccess network. Each of the base stations is commonly controlled by anaccess network controller. For example, a third generation (3G) radioaccess network controller (RNC) or a more conventional base stationcontroller (BSC) of the second generation (2G) standards may be used forsuch purposes. The access network controller may be connected toappropriate core network entities of the cellular system, such as a MSC(mobile switching centre) and/or SGSN (serving general packet radioservice support node), via a suitable interface arrangement.

The home network 2 of the user equipment 1 may also be provided with ahome location register 6 or similar subscriber database.

Any appropriate mobile user equipment adapted for the communication withthe access network may be used to connect the network. For example, auser may access the cellular network by means of a user equipment suchas a Personal computer (PC), Personal Data Assistant (PDA), mobilestation (MS) such as a mobile phone and so on. One skilled in the art isfamiliar with the features and operation of a typical mobile userequipment such as a mobile station. Thus it is sufficient to note that auser may use a mobile user equipment for tasks such as for making andreceiving phone calls, for receiving and sending data from and to thenetwork and for experiencing e.g. multimedia content.

A user equipment within a radio access network may communicate with aradio network controller via radio network channels which are typicallyreferred to as radio bearers (RB). Each user equipment may have one ormore radio network channel open at any one time with the radio networkcontroller.

A mobile user equipment is typically provided with processor and memorymeans for accomplishing these tasks. A mobile user equipment may includeappropriate antenna elements for wirelessly receiving and transmittingsignals from and to base stations of the mobile communication network. Amobile user equipment may also be provided with a display for displayingimages and other graphical information for the user of the mobile userequipment. Speaker means may also be provided. The operation of a mobileuser equipment may be controlled by means of an appropriate userinterface such as control buttons, voice commands and so on.

It shall be appreciated that a number of user equipment may be incommunication via the cellular system although only one mobile userequipment is shown in FIG. 1 for clarity.

The location of the mobile user equipment 1 may vary in time as the userequipment is free to move within the coverage area of a base station andalso from a cell to another cell, and even from a network to anothernetwork. As mentioned above, the modern communication systems arecapable of providing information regarding the geographical location ofa user equipment. The geographical location may be defined, for example,on the basis of the position of the mobile user equipment relative to atleast one base station and/or based on information from a satellitebased system 9 or from other external location information resource. Thegeographical location of the user equipment may be defined, for example,in X and Y co-ordinates or in latitudes and longitudes. A possibility isto use the relation between defined radiuses and angles, e.g. based onthe spherical coordinate system or alike. It is also possible to definethe location of the base stations and/or mobile user equipment invertical directions. For example, Z co-ordinate may be used whenproviding the location information in the vertical direction. Thevertical location may be needed e.g. in mountainous environments or incities with tall buildings.

FIG. 1 shows also a location service (LCS) client 8. A location serviceclient may request for location information from the communicationsystem. The location service client 8 can thus be seen as a logicalfunctional entity that may make a request for location information ofone or more target user equipment for what ever purposes. The locationservice client typically needs to be authorized in a predefined mannerto be allowed receive at least some degree of information concerninglocation (or location history) of a target user equipment. A locationservice client 8 can be any entity that may make use of the locationinformation. The location service client may be an entity that isexternal to the communication network. The location service client mayalso be an internal client (ILCS) i.e. reside in any entity or node(including a mobile user equipment) within the communication system.Examples of location service clients include service applications suchas pure location information services, games wherein locationinformation can be utilized, fleet management applications and emergencyservices. A location sensitive service application may use locationinformation for various purposes, for example to enhance usability ofthe service or for content segmentation.

In order to provide location information, the communication system maybe provided with various different means for determining thegeographical location of a target user equipment. The locationinformation may be obtained by using one or a plurality of appropriatelocation techniques. A location service entity may include capabilitiessuch as functions for handling Service Area Identities (SAI), AssistedGPS (A-GPS) and OTDOA. A serving location service entity 10 maycommunicate with the user equipment 1, for example to request terminalbased positioning information, to request terminal measurements or todeliver location services assistance data.

There are several ways how the location service entities may communicatewith the user equipment on user plane. According to a preferred approachthe location service entity and/or the user equipment is addressed bymeans of an IP address thereof. Use of IP addresses allows establishmentof dedicated IP sessions between a user equipment and a locationservices entity.

The user equipment 1 may be adapted to perform location measurementsand/or calculations, and thus the location determination may beperformed at least partially at the user equipment 1. The user equipmentmay be configured to process information received from external sources.At least a part of the location information may be provided based oninformation provided by system that is separate from the communicationsystem. For example, information may be provided by means of a satellitebased system 9, such the Global Positioning System (GPS), differentialGPS, Galileo or similar. The user equipment may be a GPS enabledterminal. That is, the user equipment may be provided with a GPSreceiver and means for processing GPS data.

A location service (LCS) functionality in association with acommunication system may be provided by various entities. The client 8may send the request to a specific location service server comprisingcomponents and bearers needed to serve LCS clients. The server mayprovide a platform which will enable the support of location basedservices in parallel with other communication services such as speech,data, messaging, other teleservices, user applications and supplementaryservices. A location service server may thus provide the client, onrequest or periodically, the current or most recent geographic location(if available) of the target user equipment or, if the location fails,an error indication and optionally the reason for the failure.

A location service may be provided by various manners in associationwith a communication system. FIG. 1 shows an arrangement wherein alocation service server 10 is provided in association with the network 3and a location service 20 in association with the network 2. However, itis understood that a location service functionality associated with anetwork may comprise a number a location service entities, for example acontrolling location service server in addition to at least one userplane location server. A non-limiting example of such arrangements isgiven in 3G specifications wherein a location service (LCS) serverentity referred to as a Gateway Mobile Location Center (GMLC) isspecified to provide an entity managing the location services. The GMLCis for gathering and storing various data that may be used in provisionof location information for the location service clients (LCS clients).However, since a distributed location service is not required in allembodiments, only one location service entity per network is shown inFIG. 1.

Location data may be provided to an appropriate location service entityfrom various sources connected to the communication system. Locationdata may also be processed in the user equipment that is provided withappropriate processing capacity. The user equipment may then provide thelocation service entity or the client with processed data such aslocation co-ordinates.

It is possible to signal data on a user plane connection in associationwith location information services. For example, packet switchedinternet protocol (IP) user plane connection may be provided for suchcommunication in parallel with another user plane communication mediasuch as PDP (packet data protocol) context, data call, WLAN (WirelessLAN) communications and so on. Messages that relate to the providinglocation information, for example location information requests,responses and assistance data, may be delivered via a IP connection thathas been established in response to a location request.

Communication of telecommunication traffic such as voice, data ormultimedia content to and/or from the user equipment 1 visiting network3 is carried on a user plane. Signaling of messages that support theactual communication are then carried on a control plane.

In the embodiments communication of information supporting the operationof a location information service may also be carried on the user planebetween a user equipment 1 and a serving local location service entity10. In such scenario a client application 8 may request for userposition from a serving local location service entity 10. Subsequent tosuch request data may be communicated on a user plane IP sessionestablished between the mobile user equipment 1 and the local locationservice entity 10.

In FIG. 1 a user plane session 12 is shown as being established betweenthe user equipment 1 and the location service entity 10 of the visitednetwork 3. It shall be appreciated that a user plane IP session may alsoestablished between the user equipment 1 and a location service entity20 of the home network 2 of the user equipment 1.

A GPS receiver 14 (see FIG. 3) may be integrated to the user equipment 1in applications wherein the GPS is used for provision of the locationinformation, for example in the so called Assisted GPS (A-GPS) methods.In such applications assistance data may need to be communicated from anetwork server to a GPS enabled user equipment to enhance the operationthereof. For example, sensitivity, coverage and response time may beenhanced by means of additional information assisting in theprovisioning of the location data. The GPS assistance data for the A-GPSarrangement may be transferred to the user equipment using the userplane IP connection. The A-GPS assistance data may be transferred overthe IP connection without any proprietary connection to an assistanceserver. It shall be appreciated that assistance data may be provided byan entity that may also perform at least a part of the required locationcalculation services.

It should be noted that some of the assisted GPS procedures in the userequipment may require initial rough location information estimate, forexample a cell level knowledge of the position of the user equipment.This information may also be provided for the user equipment by means ofthe assistance data.

It is also possible that a GPS enabled user equipment produces GPSassistance data. The assistance data can then be reported to appropriatelocation service entities using a dedicated IP session.

Standard based protocol parameters may be used for the communications.For example, when collecting assistance data from the GPS enable userequipment the parameters can be based on the 3G definitions.

The following will describe some exemplifying embodiments with referenceto emergency calls. Emergency calls are an example of calls wherein itmay be necessary to establish the location of a party of the call suchthat the location determination procedure is initiated automatically inresponse to detection of the type of a call.

Reference is now made to the flowchart of FIG. 2 illustrating a possibleflow of events in association with an emergency call made at step 100 bya user equipment. A mobile user equipment making a call may beconfigured to detect that the dialed number is an emergency call number.An emergency call associated location determination may then be based ona procedure including steps wherein at step 102 the user equipmentdetects that the call is an emergency call. The detection functionalitymay be provided by manners. For example, the user equipment may beprovided with a table of general emergency numbers, for example a tableincluding numbers 911, 112, 10022, 999 and so on. A controller may thenmonitor for the calls, and if a call is initiated to one of thesenumbers, it is concluded by the processor that the call is an emergencycall.

If a mobile user equipment detects that a call is an emergency call, itmay then initiate at step 104 a user-plane connection to a user planelocation service server. At this stage appropriate routing informationmay be utilized in the set-up of the user plane connection. Someexemplifying possibilities for providing the user equipment withappropriate routing information and use thereof will be described inmore detail later with reference to FIGS. 3 to 6.

A user plane connection may be needed for example since user equipmentmay need to receive assistance data to determine its location. In FIG. 2assistance data is communicated to the user equipment at step 106. Themobile user equipment may also use the user plane for communication ofinformation about its location or measurements to a user plane server.For example, such data may be communicated on the user plane in the caseof so-called mobile station (MS) assisted A-GPS.

At step 108 information associated with location determinations may becommunicated from the user equipment to the local location serviceserver. The local location service server may then communicateinformation regarding the location of the target user equipment to theclient application.

It is also possible that an appropriate network element rather that theuser equipment first recognizes that the call is an emergency call. Thenetwork element may be, for example, a Mobile Switching Center (MSC), aServing General Packet Radio Service Support Node (SGSN), a GatewayGeneral Packet Radio Service Support Node (GGSN) or any otherappropriate network controller. According to a possibility a PublicSafety Answering Point (PSAP) provides the detecting entity. Subsequentto detection the PSAP may request from an appropriate location serviceentity location information related to a target mobile user equipment,i.e. a mobile user equipment which has requested for an emergency callconnection. Thus the detection step may also be performed in anotherentity than the user equipment requesting for the connection.

A network element rather than a mobile user equipment may also initiatelocation procedures utilizing user plane communications. For example, auser plane location service entity 10 may initiate a user-planeconnection to the mobile station 1. Location related information maythen be exchanged on the user plane to obtain the location estimate forthe mobile station. However, a roaming mobile station may need to beable to verify that the network entity is authorized to receiveinformation about the location of the user equipment.

In the embodiments a roaming user equipment may use information aboutthe user plane address of the server of the visited network to initiateuser plane connection set-up or to verify that the server is authorizedto be a party of exchange of information. The user plane address of thevisited server may be provided to the user equipment in various manners,as will be explained below with reference to FIGS. 3 to 6.

Once a location estimate is determined, it can be conveyed to a LCSclient, for example to a Public Safety Answering Point (PSAP). If acentral location service entity such as a GMLC is provided in thenetwork, the location estimate may be delivered to the client from theGMLC. This is an implementation issue, and may depend on the standardsthe communication system is based on.

With references to FIG. 3, a possibility is to store information aboutthe user plane address for the location service entity of the visitednetwork in a memory 15 of a mobile user equipment 1. The information 16may comprise addresses of all legitimate location service entities whichassociate with network identities (NW ID) the user equipment 1 may roaminto. For example, a user identity module may contain a list ofaddresses of legitimate secure user plane location (SUPL) servers ofnetworks the subscriber is allowed to roam into. The user identitymodule may comprise, for example, a Subscriber Identity Module (SIM)card of a mobile station.

When a roaming mobile user equipment needs to request information from aroamed location service server, it can find the correct user planeaddress based on the identity of the roamed network. If the mobile userequipment receives a location request from a local location serviceserver, it can validate the request by checking the list. If the checkis positive, the request is authorized to proceed further. If the servercannot be authorized based on the list, the request is rejected. Theprocessing of the request may be performed by processor 18 of the userequipment.

The addresses of the location service servers may be updated from theinitially stored addresses. New addresses may also be added, andaddresses may be deleted. The update may be done remotely, for exampleon request or periodically.

FIG. 4 shows an embodiment wherein routing information is provided for aroaming mobile user equipment 1 whenever such information is needed. Inaccordance with this embodiment a mobile user equipment is configuredsuch that it knows a connection identifier of a location service server20 of the home network thereof and may thus establish a connection tothe home network server 20 from a roamed network.

The mobile user equipment 1 may provide in message 30 appropriateinformation identifying the roamed network to the home network server20. The home network server 20 has a database 21 containing the IPaddresses of the location service servers of other networks whereroaming is possible. Based on the identity information the home networkserver 20 may then fetch the relevant address information and provide itin message 31 to the roaming mobile user equipment 1. The mobile userequipment 1 may then use the address information for establishing aconnection to the local location service server 10 of the roamednetwork.

The mobile user equipment 1 may end at this stage the connection to thehome server 20 and establish a new connection to the server 10 of theroamed network by sending a request 32 for location assistance. Themobile user equipment may thus obtain local and thus proper locationassistance data in message 33 from the local server 10 rather than fromthe home network. If necessary, the mobile user equipment 1 may send inmessage 34 its location to the local server 10.

FIG. 5 shows an embodiment wherein a mobile user equipment 1 which knowsthe connection identifier of a location service server 20 of the homenetwork first establishes a connection to the home network server, seemessage 40. Message 40 provides the home server 20 with the identity ofa roamed network and a request for assistance data.

The relevant user plane address information for a location serviceserver 10 of the visited network is made available for the home networkserver 20. For example, the home network server 20 may be provided witha database 21 containing the IP addresses of location service servers ofother networks where roaming is possible for the mobile user equipment1. The home network server 10 may use this information to form aconnection to the server 10 of the roamed network, see message 41.

The home server 20 may then act as a transparent router between themobile user equipment 1 and the roamed server 10, see messages 42 and43. In message 42 the roamed server 10 is provided with a request forlocation assistance data. The mobile user equipment 1 may then obtainlocation assistance data from the roamed server 10 in message 42 routedvia the home server 20. If necessary, the mobile user equipment may sendits location in message 43 to the roamed server 10, for example foremergency call location purposes.

FIG. 6 shows an embodiment for handling a location request 50 by avisited location service server 10. If a mobile user equipment 1 knowsonly the IP address or other identifier useful for forming a user planeconnection of a home network location service server 20, the mobile userequipment 1 may establish a connection to the home server 20. In message51 the home server 20 is provided with the identity of the roamed server10. Other additional information, for example, the identity of theroamed network may be included in this message. The home server 20 isprovided with a database 21 containing IP addresses of legitimatelocation service servers of other networks where roaming is possible.

The home server may check if the identity of the roamed server matchesany of the addresses stored in a database 21 thereof. The home servermay then inform the mobile user equipment in message 52 about theresults of the check. The mobile user equipment 1 may then end theconnection to the home server 20. If the check indicated that the roamedserver may be provided with the location information, the mobile stationmay then respond to the request from the location service server 10 ofthe roamed network, see message 53.

FIG. 7 shows a further embodiment which may be useful when the mobilestation 1 is not able to identify a network it has roamed into. Thisproblem may be addressed by an arrangement wherein a home networklocation service server 20 contacts, upon receipt of a message 61 fromthe user equipment 1, a Home Location Register (HLR) 6 of the subscriberand requests by message 62 for the identifier of the roamed network. TheHLR then return the identifier in message 63. This may be accomplished,for example, by using existing 3GPP standardized Mobile Application Part(MAP) signaling.

It shall be appreciated that although the above describes the inventionin with reference to Internet Protocol (IP) user plane sessions, this isnot the only possibility for the user plane communication. Thecommunication may occur, for example, based on signaling by means of aPDP context, short message service (SMS), data call and so on.

It should be appreciated that whilst embodiments of the presentinvention have been described in relation to mobile stations,embodiments of the present invention are applicable to any othersuitable type of user equipment.

It is also noted herein that while the above describes exemplifyingembodiments of the invention, there are several variations andmodifications which may be made to the disclosed solution withoutdeparting from the scope of the present invention as defined in theappended claims.

1. A method comprising: using, at user equipment, address information ofat least one location service entity associated with a visitedcommunication network, said address information received from a locationservice entity of a home network of the user equipment, said addressinformation enabling the user equipment to communicate on a user planeconnection with the at least one location service entity associated witha visited communication network, when the user equipment is visiting acommunication network other than the home network of the user equipment;configuring the user equipment to communicate location information withthe at least one location service entity associated with the visitedcommunication network via the user plane connection in the visitedcommunication network; establishing a user plane connection between theuser equipment and the location service entity of the home network;establishing a user plane connection between the location service entityof the home network and the at least one location service entityassociated with the visited communication network; and routing userplane communication between the user equipment and the at least onelocation service entity associated with the visited communicationnetwork via the location service entity of the home network.
 2. Themethod as claimed in claim 1, wherein the receiving of informationenabling the user equipment to communicate with at least one locationservice entity comprises storing the information in the user equipment.3. The method as claimed in claim 2, wherein the storing comprisesstoring a plurality of user plane addresses for location serviceentities associated with a plurality of communication networks.
 4. Themethod as claimed in claim 2, wherein the storing comprises storing theinformation in a subscriber identity module of the user equipment. 5.The method as claimed in claim 1, further comprising: establishing aconnection between the user equipment and the at least one locationservice entity of the home network; receiving a user plane address ofthe location service entity associated with the visited network in theuser equipment; and using the received user plane address to establishthe user plane connection between the user equipment and the locationservice entity of the visited network.
 6. The method as claimed in claim1, wherein the receiving of information enabling the user equipment tocommunicate with the at least one location service entity comprisesreceiving, at the user equipment, the address of the at least onelocation service entity of the home network, wherein the method furthercomprises: establishing a user plane connection between the userequipment and a location service entity of the visited network via thelocation service entity of the home network.
 7. The method as claimed inclaim 1, wherein the configuring of the user equipment to communicatewith the at least one location service entity comprises initiatingestablishment of a user plane connection by the user equipment based onsaid address information obtained by the user equipment.
 8. The methodas claimed in claim 1, wherein the configuring of the user equipment tocommunicate with the at least one location service entity comprisesinitiating, by a location service entity of the visited network,establishment of a user plane connection between the location serviceentity of the visited network and the user equipment.
 9. The method asclaimed in claim 8, further comprising: authorizing the location serviceentity of the visited network based on said address information receivedby the user equipment.
 10. The method as claimed in claim 1, furthercomprising: sending an inquiry for an identity of the visited network.11. The method as claimed in claim 1, wherein the address informationcomprises a user plane address of a secure user plane location server.12. The method as claimed in claim 1, further comprising: detectingwhether location information is needed in association with a callinitiated by the user equipment.
 13. The method as claimed in claim 10,further comprising: detecting that the call is an emergency call.
 14. Asystem, comprising: a home location service entity of user equipment incommunication with a communication system, the communication systemcomprising a plurality of networks, wherein one of the networks is ahome network of the user equipment and at least one other network is anetwork that the user equipment is allowed to visit; and at least onefurther location service entity associated with the at least one othernetwork, wherein the user equipment is configured to use addressinformation regarding at least one user plane address of the at leastone further location service entity associated with the at least oneother network, said address information received from the home locationservice entity, and to use said address information to communicatelocation information with the at least one further location serviceentity on a user plane when visiting a network other than the homenetwork; wherein the communication system is configured to establish auser plane connection between the user equipment and the locationservice entity of the home network, establish a user plane connectionbetween the location service entity of the home network and the at leastone location service entity associated with the visited communicationnetwork, and route user plane communication between the user equipmentand the at least one location service entity associated with the visitedcommunication network via the location service entity of the homenetwork.
 15. An apparatus, comprising: a processor configured to causethe apparatus to provide to user equipment, from a location serviceentity of a home network of the user equipment address information of atleast one location service entity associated with a visitedcommunication network of the user equipment, that enables the userequipment to communicate on a user plane connection with the at leastone location service entity associated with the visited communicationnetwork when the user equipment is visiting a communication networkother than the home network of the user equipment, establish a userplane connection between the user equipment and the location serviceentity of the home network; establish a user plane connection betweenthe location service entity of the home network and the at least onelocation service entity associated with the visited communicationnetwork; and route user plane communication between the user equipmentand the at least one location service entity associated with the visitedcommunication network via the location service entity of the homenetwork.
 16. The apparatus as claimed in claim 15, further comprising:storage configured to store the information.
 17. The apparatus asclaimed in claim 16, wherein the storage is further configured to storea plurality of user plane addresses for location service entitiesassociated with a plurality of communication networks.
 18. The apparatusas claimed in claim 15, further comprising: a receiver configured toreceive an inquiry for an identity of the visited network.
 19. Theapparatus as claimed in claim 15, wherein the address informationcomprises a user plane address of a secure user plane location server.20. The apparatus as claimed in claim 15, wherein the processor isfurther configured to detect whether location information is needed inassociation with a call initiated by the user equipment.
 21. Theapparatus as claimed in claim 20, wherein the call is an emergency call.22. The apparatus as claimed in claim 15, wherein the apparatus iscomprised in a location service entity of the home network.
 23. A methodcomprising: providing a user equipment from a location service entity ofa home network of the user equipment, with address information of atleast one location service entity associated with a visitedcommunication network of the user equipment, said address informationenabling the user equipment to communicate on a user plane connectionwith the at least one location service entity associated with thevisited communication network when the user equipment is visiting acommunication network other than the home network of the user equipment;establishing a user plane connection between the user equipment and thelocation service entity of the home network; establishing a user planeconnection between the location service entity of the home network andthe at least one location service entity associated with the visitedcommunication network; and routing user plane communication between theuser equipment and the at least one location service entity associatedwith the visited communication network via the location service entityof the home network.
 24. The method as claimed in claim 23, comprisingestablishing a connection between the at least one location serviceentity of the home network and the user equipment, sending a user planeaddress of the location service entity associated with the visitednetwork to the user equipment, and using the sent user plane address forestablishing the user plane connection between the location serviceentity of the visited network and the user equipment.
 25. The method asclaimed in claim 23, wherein the providing of information enabling theuser equipment to communicate with at least one location service entitycomprises providing the user equipment with an address of the at leastone location service entity of the home network, wherein the methodcomprises establishing the user plane connection between the userequipment and the location service entity of the visited network via thelocation service entity of the home network.
 26. The method as claimedin claim 25, comprising establishing a user plane connection between theuser equipment and the location service entity of the home network,establishing a connection between the location service entity of thehome network and the location service entity of the visited network, androuting user plane communication between the user equipment and thelocation service entity of the visited network via the location serviceentity of the home network.
 27. The method as claimed in claim 23,wherein the configuring the at least one location service entity tocommunicate with the user equipment comprises initiating, by thelocation service entity of the visited network, establishment of theuser plane connection between the location service entity of the visitednetwork and the user equipment.
 28. The method as claimed in claim 27,comprising authorizing the location service entity of the visitednetwork based on said information provided for the user equipment. 29.The method as claimed in claim 23, comprising sending an enquiry for anidentity of the visited network.
 30. The method as claimed in claim 23,wherein the address information comprises a user plane address of asecure user plane location server.
 31. The method as claimed in claim23, comprising detecting whether location information is needed inassociation with a call initiated by the user equipment.
 32. The methodas claimed in claim 31, comprising detecting that the call is anemergency call.
 33. An apparatus, comprising: a processor configured touse address information of at least one location service entityassociated with a visited communication network, said addressinformation received from a location service entity of a home network ofthe user equipment, said address information enabling the apparatus tocommunicate on a user plane connection with the at least one locationservice entity associated with the visited communication network, whenthe apparatus is visiting a communication network other than the homenetwork of the apparatus; configure the apparatus to communicatelocation information with the at least one location service entityassociated with the visited communication network via the user planeconnection in the visited communication network; establish a user planeconnection between the apparatus and the location service entity of thehome network; establish a user plane connection between the locationservice entity of the home network and the at least one location serviceentity associated with the visited communication network; and route userplane communication between the user equipment and the at least onelocation service entity associated with the visited communicationnetwork via the location service entity of the home network.
 34. Theapparatus as claimed in claim 33, wherein the processor is furtherconfigured to store the address information enabling the apparatus tocommunicate with at least one location service entity in storage. 35.The apparatus as claimed in claim 34, wherein the processor is furtherconfigured to store a plurality of user plane addresses for locationservice entities associated with a plurality of communication networksin the storage.
 36. The apparatus as claimed in claim 34, wherein theprocessor is further configured to store the information in a subscriberidentity module of the apparatus.
 37. The apparatus as claimed in claim33, wherein the processor is further configured to establish aconnection between the apparatus and the at least one location serviceentity of the home network, receive a user plane address of the locationservice entity associated with the visited network, and use the receiveduser plane address to establish the user plane connection between theapparatus and the location service entity of the visited network. 38.The apparatus as claimed in claim 33, wherein the processor is furtherconfigured to receive an address of the at least one location serviceentity of the home network and to establish a user plane connectionbetween the apparatus and a location service entity of the visitednetwork via the location service entity of the home network.
 39. Theapparatus as claimed in claim 33, wherein the processor is furtherconfigured to initiate establishment of the user plane connection basedon the received information.
 40. The apparatus as claimed in claim 33,wherein the processor is further configured to initiate by theapparatus, establishment of the user plane connection between thelocation service entity of the visited network and the apparatus. 41.The apparatus as claimed in claim 40, wherein the processor is furtherconfigured to authorize the location service entity of the visitednetwork based on the received information.
 42. The apparatus as claimedin claim 33, wherein the processor is further configured to send aninquiry for an identity of the visited network.
 43. The apparatus asclaimed in claim 33, wherein the address information comprises a userplane address of a secure user plane location server.
 44. The apparatusas claimed in claim 33, wherein the processor is further configured todetect whether location information is needed in association with a callinitiated by the apparatus.
 45. The apparatus as claimed in claim 44,wherein the processor is further configured to detect that the call isan emergency call.